To find the largest possible equal groups that can be formed with no students left over, we need to find the greatest common factor (GCF) of 28 and 36.
The prime factorization of 28 is 2 x 2 x 7, and the prime factorization of 36 is 2 x 2 x 3 x 3.
The common factors are 2 x 2 = 4.
Therefore, the largest possible equal groups that can be formed with no students left over is 4.
For the chorus with 28 students, there will be 28 ÷ 4 = 7 groups of 4 students each.
For the chorus with 36 students, there will be 36 ÷ 4 = 9 groups of 4 students each.
So, each group will have 4 students.